Search found 8 matches

by Yehuda
2 months ago
Forum: Modeling
Topic: How to ranging variables
Replies: 5
Views: 275

Re: How to ranging variables

Thank you again.

So I tried your suggestion but it causes another problem. Now the model is declaring an endogenous problem and it prohibits the use of $ operation.

I thought that the ranging issue will be easy to defined, but it's apparently not.

Anyway, thanks a lot!

Yehuda
by Yehuda
2 months ago
Forum: Modeling
Topic: How to ranging variables
Replies: 5
Views: 275

Re: How to ranging variables

Thank for your response. I'll try to make it clear. Since small values for one of the variables in my model are causing an infeasible solution, I'm looking for a way to solve this problem. However, a simple restriction like X>1 is inapplicable because I want to give this variable the option to be ze...
by Yehuda
3 months ago
Forum: Modeling
Topic: How to ranging variables
Replies: 5
Views: 275

How to ranging variables

Hi all, I'm having trouble with variables that the model chooses to give them very small values but not zero, values that are not reasonable for these variables. My question is how can I give the model a range for these variables such that: on the one hand they can be zero and on the other hand they...
by Yehuda
3 months ago
Forum: Modeling
Topic: Solving the division by zero problem
Replies: 2
Views: 199

Re: Solving the division by zero problem

Thank you, Job.

I already tried your suggestion but it causes me other problems.
I thought that there is a simple solution to my problem, but it seems there isn't.

Anyway, thanks for your response.

Yehuda
by Yehuda
3 months ago
Forum: Modeling
Topic: Solving the division by zero problem
Replies: 2
Views: 199

Solving the division by zero problem

Hi all, My model contains, by definition, division by zero possibilities. In a nutshell, the model needs to decide how much water to transfer in a pipeline network. The pipeline network includes some pipes which the model can decide not to use. Due to some other equations, the model confronts the di...
by Yehuda
5 months ago
Forum: Solvers
Topic: *** Failure calling solver: CONOPT4 (rc=1). What does it mean?
Replies: 5
Views: 504

Re: *** Failure calling solver: CONOPT4 (rc=1). What does it means?

Thank you Michael. In other words, you mean that I need to purchase an updated version? I've been working with GAMS for about two and a half years, and this is the second time I've been asking for help from you, and this is the second time the solution is to buy another version. I was wondering if e...
by Yehuda
5 months ago
Forum: Solvers
Topic: *** Failure calling solver: CONOPT4 (rc=1). What does it mean?
Replies: 5
Views: 504

Re: *** Failure calling solver: CONOPT4 (rc=1). What does it means?

First of all, thank you for the quick answer. Second, I do run a NLP model and my GAMS version is 24.9.2, which I bought specifically for CONOPT4 (due to previous problems). The strange thing is that under certain conditions the model runs and reaches an optimal solution, and under other conditions,...
by Yehuda
5 months ago
Forum: Solvers
Topic: *** Failure calling solver: CONOPT4 (rc=1). What does it mean?
Replies: 5
Views: 504

*** Failure calling solver: CONOPT4 (rc=1). What does it mean?

Hi everyone,

I run my model and receive that message:

*** Failure calling solver: CONOPT4 (rc=1)

What does it means and how can I solve it?

Thank you.